Secure Storage/Parking for Motorcycle?

I park my motorcycle in a proper allocated bay on Hopton Street and apart from the exposure to the elements (which can't be foreseen!) it was recently knocked over (1 of 3 bikes that were) by a reversing van who surveyed the damage and then drove off! Lots of damage which I now have to pay for.

So I was wondering whether anyone has an off street/undercover/underground parking space that they don't use close by? It doesn't need to be a parking space for a car, just anywhere off the street that would be securely away from other traffic, but would allow me access to it at any time? Bikes obviously don't take up much space!